“Pool”, by David Macdonald, features a man in the center of the image who appears to be climbing down a ladder. (I suppose he could be climbing up, but since he is looking down, that is probably the direction that he is headed. Either way, the illusion is the same!) The top and the bottom of the ladder are connected to two sections of patio that surround the pool. This leads to the obvious question – how exactly can be be climbing down (or up) the ladder?